SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18591e18ca87d451f4f44ab8295589b1fa317012b80237a0768ea1cdf6a3dfe1' 
  AND token = 'b8UEGoVlV4H5ClOJY0BR7KHtqf3m+nwgZvWo9mzw/DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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