SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '983f6971d042afed61f7f60df582f027080769c162fee49890cc6da3445f3d00' 
  AND token = '8tbxL0QQOVwzXXCDWeBLx5fZeB8jJps3IM2LhfVL9gA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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