SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce154924689ee870ed22d601269ac1718a8037e8002a15c6eda816d860db173f' 
  AND token = 'CEVpd9ecS4YJbxDsNglvM1IocP5wUW6brRLUFaVGaUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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