SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25b50c59c2df1ec1138afc65402afee4a14d492c4ba77489258854e9898789aa' 
  AND token = 'Xs/5aySGXcvePhW7TO0CwfOrY/n1PNAG4m676TN9Zbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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