SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '294f0f30ce20c0426686b5ad99a3d519e228b8020c23ff97a601baf9be82ec5c' 
  AND token = 'lj2EPQP0K6CMJ6CiTsFFKHI5ylGLP7G1Fa+tXvQ/kaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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