SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cc9935353b8c619dca18f4f5f376912bb734fca3897ba1dae1620f05f7b36944' 
  AND token = 'uJJaID82TZv6+8xGK8E8cVCEGXRu9797dqcXyCkhi7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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