SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d115dbfbd3fc14db838686548ea2afe7ff3bc779b485c7aa957a332ae1dc88d' 
  AND token = 'VbjBa6ZEttE/t0KM9Ckh3JVPOjKChoOEqWIpG+z5k/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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