SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c26883a597213fdf0afd28df6dd21aeff1b6fb62d54db3c4566029c7cedf271' 
  AND token = 'WoKTTlhlmlQASmyumdVuxH4kriZ94vaSEBLzf1vDsk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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