SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '441d9955043bcf43604f91c0c69c5fc2f0e3901b3031167a307b08c5b9a4a589' 
  AND token = 'UQr/yoQ2TrtuvbcDSGqmz1TwhUq6QNgZIenKkylv79g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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