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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4cefe08a717dd0b4c07e1ae53691d0be8542c5043de87b14ee9c7a6feb03e0d5' 
  AND token = 'xxkZhZD/zuQ+d7LgwFJGK7AkfIetUDL2Vpqw7Hr5xDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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