SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2477ab260f3a9b60b8946ba3d23f4f59e30bd93367d58463197b4cdfff0f0518' 
  AND token = 'LFaUV7XcWCL3J6oHJNwLfy+NxbLJnJppkBPAK6QXE+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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