SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63f193e1e6cb6bf58596b6cb27aa8f1b16b75c1f6d30407f879167874f9d304e' 
  AND token = 'rFciJH6hnVVZbh80LCw2Ws7x5jYXMZ3uXPd+PrrZpsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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