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SELECT 
  cscart_state_descriptions.state 
FROM 
  cscart_states 
  LEFT JOIN cscart_state_descriptions ON cscart_state_descriptions.state_id = cscart_states.state_id 
  AND cscart_state_descriptions.lang_code = 'en' 
WHERE 
  cscart_states.country_code = 'UG' 
  AND cscart_states.code = ''

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}