SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '794f4799152c4136b40f40e6f569715cd4b6b89eef9d636955e6a20f432698af' 
  AND token = 'aypU5mZhnqzKz8jY8VIdhTRZ/PBn2DfmfgXm0+PO/IM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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