SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3870de57dd19a8d52b156941040e2987c1eb7c460f0220e1306d632ff2bd58e3' 
  AND token = 'QgobJKmgV/ThzZGBHUdrO+awe9F/Iw/UczEV7uKio+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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