SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ae661bba622264a93381019e1005bc7c2693bac3d0f5570f5bdb34f4b778c881' 
  AND token = 'pdb6arC+Xh/riSheo3GLKRWZGf3v9K4Fv0heutAR9Tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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