SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3840e047dc749fe950884ecb5b3f9822438704b7bfa35bf9e7facdb3d67b1c97' 
  AND token = '+l93qwKxYPZOJPODkggkwOesdl6OWd6soz/+E9unSws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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