SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dc7227884830a25c911108656da6f653732676bcddd4a475cc238dfe18a6b274' 
  AND token = 'Kalwo/GOJ1YiP2Yp6qyCc6rEC78VXL3t9nBEFP1NZvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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