SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ec9fbeadbcbbdbcf9987a8dba61f572b611cacb6b751e7cd096c4b32aa5f92' 
  AND token = 'QmeAB6EiZWdlXU6Q7Y+psB3WLQ7ZeolW3S4PqO09LNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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