SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe84cab4653ad71e99a970a7a5628e430108302c92ced7b0c5b1d94a6b56a2c4' 
  AND token = '4H+S1OZOBevbfb6icNfupNlWSv8gooY6/K4T7kN8xck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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