SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dcbb760a3df4b6cf8efeb5b6cd5898f5f55176b8f4dbdd3b475ff44496f70944' 
  AND token = 'gXFwxT2nIZjV/tb9xRg/Nng6UzuumsC54TyqUL0WIH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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