SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff590d4fc322502d082188c4588cd0119bb11ea1dafd6f54d8c5b42a5dadf4bc' 
  AND token = 'DJt/DkniTt8NvtZNaqqpkT5L3cSEV0umiTztYS/HqhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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