SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '30bd26d66a28ff8337fb874472c6c0f83a5346d5285337aadf23beacb550d823' 
  AND token = 'tTH4NoaNmCXHeGB0+vqNSUpBJjC6GXC7KWNwV/X0UO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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