SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5761c45661027c4962696d41e7afc11a95f92de3fda1dd2a78c5f74d466b140' 
  AND token = 'JFSaQYxr7YeMNPYJA7AX2fXfKooSHUYtjIj6qOt+JBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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