SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8457af90723b6e6193d1df835741c133623fd1535f5b4fed5dd2843aa1788b98' 
  AND token = 'N4g/3sxquowy1V+/hYlPD9IdvA0aJgt1jF2DiHnq7sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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