SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d324fd6613bfab91fbb373a6927d228205387ff18a604f18b79e33788c2cc0' 
  AND token = 'slKnbC3g1NPLGGVxkSxhPNqrPFCsHXJRisMQKlXVjFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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