SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '492405c21e3bf0fb3307438749c0e7258142a5e6cdfaba1557fac381c4733e4a' 
  AND token = '4Vq98/GB+mXFfAlGjpGJhqC0B8uDY9Stz8ikA0XeRUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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