SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62a9b1e9b92dc6a280ba8c25230bbf727ff02f0eb381621799208141c84f3517' 
  AND token = 'LKloG/o2p3jH8gx5h13OdQiOCTureZjDAWRfreeD5Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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