SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d2bf80a90e8402b95fb0cc67d4fd0a5914c32dcf6492c9c0899db18c8783868' 
  AND token = 'wmuzwdIysf3k6es99HnfiPsQ88PCuV6YriMs0B5jXrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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