SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ff0f25bd5df05fe8706e4f879f2eb42671eb6b36b081b61074da071371cc2d6' 
  AND token = 'oXjEj3GBjosOzH7GVb/CSvA3+uUIdDpGjj6xvCK7PYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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