SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33104855cb41df1128f8c85d9e7f52809728eab3ec70a6fc8504c4b3f64c5906' 
  AND token = 'GWB9CK6ZgJPyTOLkMiySa1JfS3b/HME1WMyBFus2gM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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