SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd09da03d7474c1a4100d4a3bbb1547914134971381d7418a65ad5814480705fb' 
  AND token = '6avITuW7XbCQrotRwyLyoK4jRw86BT3oWQe0EzWuLb8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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