SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef1998d14572181e20ac3af42be830ef92420200beb010f3bdf46924b72b455' 
  AND token = '+iRMp6PXxvTMS7tDpWu/zvDjSOOywoTFf+gADSefon8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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