SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278230ea25d7583f01045982148812ae1e215c87ad07e68711295061cff984c2' 
  AND token = 'E6ZYUWrlei5nlUYZDToo3gEdcFLJviPjXDAmzliQ6Vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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