SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '821223bc1cf9974c61410495cd9f01ab1146048b920f8ef7db5555ef8bdf02e7' 
  AND token = '2pujnxrVnCcbW6l9oXyvfYBCnhrBEc4MiXZ+Kh53Apw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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