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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5a6feef4a6c522f6328c30dc134fd308e5eee0e14fc56ffad9215f9b7acdd096' 
  AND token = 'dR7IT06j8BiFTsmQ7ZAIbjqIdwBLklF2fCapJIWQiBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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