SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'af280fb0ed7137af0e4db7a5b825e9a84dc471130d9876f2bb62808f1e6d69d1' 
  AND token = 'GWqSc5JHntMkEvjcXpckZ+4HFxxolU/XZDXXrG4BtqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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