SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '271df2525e74d2d545f2e77bcf2840932aecbaffe5d3d21a9d67d0ef993cea44' 
  AND token = 'flL8du3g6bTKJNkuQEDlDUtThfgb/4NiI+DHy0hxRL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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