SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94377aa9870db065b956a5fb907eff6f80bf7e96cd659a39f66e53a66503ec22' 
  AND token = 'AWQe1QL2yPnV/BzZ/DJGmLqnzMU7EhrhTPGbv7sejmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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