SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8358860fdb680fc1145bf6c4da14cf3a24d53c3869e05edec1e27eee2045df61' 
  AND token = 'fSBWtt+whvmzvH+OKjJBHgvMoXraSuOkoxeCbZ9WTAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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