SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db6e3d885f971d49d04d304dec91dcfd8db8cce174218be59a9c4b2045005fd9' 
  AND token = '42qyOkC7Hxs//VqOjGRaSUaOSx8SIBSuGtvm7mrNSe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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