SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cdd37acff87f471b0c3dc14d9f0c78ea995ddcc225f23c8d60a4f04d3da0c4f' 
  AND token = 'xTBnmR2XuDZZM8oIt7Uuv1+bpnuw9R1tdg/Sv6QNBGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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