SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '655c1d841d63893add8c37b8ca1618212a6b19548faea03dd334ae95d83ecbde' 
  AND token = 'KQFGYB+qsvT+zsURU40Lt/1HXEQj5XjPPUbapaHW+Go=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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