SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52aa0c33a8d95a92665f6426a69857ce35e977d044be7dec5391ea5dbcb19927' 
  AND token = 'ctifwZquEdECdjVFKa+tGshQ46YFV511fL5aTNLcu7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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