SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c86e811f2eba5dbba6705dfc6ca21a3b2e598e947b680a12dbbd08c3835616f' 
  AND token = 'RDMeld+XWZTcJGGq6BK+/1kk3x3U7WrkrA+k0KmbfIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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