SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f199b3d1b9d48eb7255ffa08228bc88fa6bd23f974dd66ef0e58331973dc0c3f' 
  AND token = 'E4hfts6jPtoQSnF6EV71k+70dtZ2fdb4NeTKVSpAhgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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