SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a70e105483f2ce3f3d071cbd006d051700cac7a7a56baae6a1a11df12f3ce474' 
  AND token = 'YZGtrWVIUK/yj2cxyR9dzcVyLG3orNudxpSK/t+Ce38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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