SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21d45ae4a86171485e1e0cafbd393eaeed834274fa322b5aadfdf75b401d3b9a' 
  AND token = 'al5TYxiZEbAhUstWy9o9f+GpGdiZo0tzMdssxhF76cM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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