SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfb70faf0b709d61337af41e29b13529fa6ff0ff28861efc6fff6f332bd01ea8' 
  AND token = 'RROZqOVuGu1vGt8j9Wt+JiWs7qi+UQ6cDg0cEWVMj+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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