SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54eda71eb1a501fb70ad0b8bb56228b98655a202f9c686614a1173cf1cd23075' 
  AND token = 'Yxiuc7lTOsWpTgQYhD5lWhUmnqGnpI4+ERnXOYytXdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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