SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '900a69f8679b680d517f7be5517fae01a8017e7c27775224f74b4ea2df79d08b' 
  AND token = 'xVyxFoZ/nzWrKqw3YVDOlXauP/xlSBZcs0IxVk5KGlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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