SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd2506468e317a5ec25cf5caf7f5f102489de0be64c93391391df35a1e6eca741' 
  AND token = 'UjOGzOBGphGJcRVt0YAFPWyYMeSwCWFgXPdd37Fv2uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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