SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67790b7765045221410f06ff275a74ae6fdaeaad640fd2f1c951cbb3cb1d5727' 
  AND token = '/EJzdcXAqKjsBWJBbqZ6SA0+ePkKyiFYKaaj/njqp0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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