SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '298d8575de0041a8ebb3887056efd3674bd8b12aa38d7d86e1705fe8c3b182ca' 
  AND token = 'E4UPFCwdleulv5Stp+HXvQwAiz4B0vTr1isD8/uszV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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