SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2a1624c81176f21e198ca37d42961c7b8b5b5a8e2804dee9b8a42c623e9ff9d' 
  AND token = 'W3MkqtIpk3kJWN6gUlEjTSrkYLJf7FP4wBWeH09uWz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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