SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2516f522590fec8e72a0bbdcc426b505ba4e17d82c3dd4cbac3912938c225978' 
  AND token = 'csvIwGcM/hTqXNWBgLEqg1GPQx+KOsREaf2PZPkK+Kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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