SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cb7cef2ad35335a60c7529bbb7a6bceb88220aa70759996b5a9549d69a9d132' 
  AND token = 'jGKpDLemU95hP4keETEDoIOK9Qm8vsKJrtv/VGQZYzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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