SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e7374a52022dd8e4f38dc5d633a520c012f8fdd565265cbeb1a35172aa91ad' 
  AND token = 'LrxmUk+Y8q18U80RwkPBgIiO28kbEQvG+Yp+VZMHS/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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