SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dd3da77e9c2b161a8f30931169c42198f67d5117fbf750fd2d338e182dd82f7' 
  AND token = '6TQN8hsKdh70+C1iigEfGeNH0DIKNL21uiehW3MFoOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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