SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efc687ef5879a4c92935a7c02cff587d40b88bd93796640cc803e5d21e34309c' 
  AND token = 'p5PHQa+RO4gp5bp6sPzodRj1hOkc0TtvSprUtdtCHGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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