SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6676f0940d637bbad08e94aed9d07d4155c4af944cd32d96f8aad9723ecbe3d' 
  AND token = 'KcP1Tb7ogBhme93e+bz6cy2DY9z8qkg7S2tTUBgfBMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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