SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '812fd061fbc0c08be93314fabde9f2af7531ecbf7f59f6cb729e2a3ade043d28' 
  AND token = 'hLOrjqNb6Cgyi7sNbOv6eBEIuzh3mSWdwO6ms/aBZNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00102

JSON explain

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