Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8b3962505e61606d5214a5e36218ca4caa8a267ed0d5926dd8df46476e9ac62' 
  AND token = 'dkYnuiXhKDtrmYA03HhVfrAjKRHK4cBLL9MdgkgABcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}