SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b66004e4360fd7cdbdc239e151cafd6294a714e3881b82bb2fccf8c0970d6a9b' 
  AND token = 'XVwgSyp+f/wliY7bsdIYZA+DzohoYdDKlviP9NpB+cU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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