SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71ea2f3f1358643df5934ca476427928c7127ddb31f17d74b1145d946c9e456' 
  AND token = 'F0Yb35DE1nJZ/YBCvMQbNLCGukvkw/PtiyRHrdLogt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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