SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a2d9fecb8fe85830ec99d76888923d45719d7e6e3f0a063d42faae853d5d1f' 
  AND token = 'kdvumcWWjJNN5GP1RGVftOFzIsWf6axGN0JUcPugaT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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