SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbf956585a4b1bda64f75a648416a28d2d1d0fc87480149270f255a49ca226f2' 
  AND token = 'nd62mPo7Co2nNeJKiRmhxxWNlWXdnfrMvEa3fS6gihM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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