SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a8dc9e859fee9d4593df3525f73227c133574162e1197dd45867cebd020eac2' 
  AND token = 'fu7CuVwHCWJ7nuqtpTVvBFCxVEleX6p0vGQxaMK4ZwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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