SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dbc193ddc7afd793f354011ac5e8d4efa79384059554cdf555e88ab3af30b2aa' 
  AND token = '+fF9tdS6KGVRNXoG/YWUGKsfzFTzr9VMMBo+jTWfxBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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