SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6768460891aafa09218460a636ca0f3e9ae626881970e25bc41eb43fb4c37104' 
  AND token = 'ZDOIYnBXjLvepbAit4upbokWZ24e7Wd4lohc3vqhZIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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