SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8c1d89610745f2a376c60f45aa3b6b73887fab9b203cd29fd4d60beb4f05ec0' 
  AND token = 'hpX2dFdzYuJOzecJSNGVm9CwlxBHXPaJuCqQLnsdZ5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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