SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5039c75fa8ca9611540215a0c2b371d8b4c40d89747f7bb1ddcb4dd7da2263d1' 
  AND token = 'zkLbfXqRarpT4P3TTkg5hxHi/P53ctCLJICAOPyUTJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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