SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19c879de72946e1437329d044cbbc52e0ddbcb8bdc69ca0cd1ebd5ce5b6c7a82' 
  AND token = 'gdNe5S+HBaetAqqHtd2OsNEkpYOA3Lv5x0wyPU9yw7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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